content: /* Copyright (C) 2016-2018 Alibaba Group Holding Limited
  
  Licensed under the Apache License, Version 2.0 (the "License");
  you may not use this file except in compliance with the License.
  You may obtain a copy of the License at
  
      http://www.apache.org/licenses/LICENSE-2.0
  
  Unless required by applicable law or agreed to in writing, software
  distributed under the License is distributed on an "AS IS" BASIS,
  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  See the License for the specific language governing permissions and
  limitations under the License.
  ==============================================================================*/
  
  // Protocol Buffers - Google's data interchange format
  // Copyright 2014 Google Inc.  All rights reserved.
  // https://developers.google.com/protocol-buffers/
  //
  // Redistribution and use in source and binary forms, with or without
  // modification, are permitted provided that the following conditions are
  // met:
  //
  //     * Redistributions of source code must retain the above copyright
  // notice, this list of conditions and the following disclaimer.
  //     * Redistributions in binary form must reproduce the above
  // copyright notice, this list of conditions and the following disclaimer
  // in the documentation and/or other materials provided with the
  // distribution.
  //     * Neither the name of Google Inc. nor the names of its
  // contributors may be used to endorse or promote products derived from
  // this software without specific prior written permission.
  //
  // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  
  package com.google.protobuf.nano;
  
  import java.io.IOException;
  import java.util.ArrayList;
  import java.util.Arrays;
  import java.util.List;
  
  /**
   * Stores unknown fields. These might be extensions or fields that the generated API doesn't
   * know about yet.
   */
  class FieldData implements Cloneable {
      private Extension<?, ?> cachedExtension;
      private Object value;
      /** The serialised values for this object. Will be cleared if getValue is called */
      private List<UnknownFieldData> unknownFieldData;
  
      <T> FieldData(Extension<?, T> extension, T newValue) {
          cachedExtension = extension;
          value = newValue;
      }
  
      FieldData() {
          unknownFieldData = new ArrayList<UnknownFieldData>();
      }
  
      void addUnknownField(UnknownFieldData unknownField) {
          unknownFieldData.add(unknownField);
      }
  
      UnknownFieldData getUnknownField(int index) {
          if (unknownFieldData == null) {
              return null;
          }
          if (index < unknownFieldData.size()) {
              return unknownFieldData.get(index);
          }
          return null;
      }
  
      int getUnknownFieldSize() {
          if (unknownFieldData == null) {
              return 0;
          }
          return unknownFieldData.size();
      }
  
      <T> T getValue(Extension<?, T> extension) {
          if (value != null){
              if (cachedExtension != extension) {  // Extension objects are singletons.
                  throw new IllegalStateException(
                          "Tried to getExtension with a differernt Extension.");
              }
          } else {
              cachedExtension = extension;
              value = extension.getValueFrom(unknownFieldData);
              unknownFieldData = null;
          }
          return (T) value;
      }
  
      <T> void setValue(Extension<?, T> extension, T newValue) {
          cachedExtension = extension;
          value = newValue;
          unknownFieldData = null;
      }
  
      int computeSerializedSize() {
          int size = 0;
          if (value != null) {
              size = cachedExtension.computeSerializedSize(value);
          } else {
              for (UnknownFieldData unknownField : unknownFieldData) {
                  size += unknownField.computeSerializedSize();
              }
          }
          return size;
      }
  
      void writeTo(CodedOutputByteBufferNano output) throws IOException {
          if (value != null) {
              cachedExtension.writeTo(value, output);
          } else {
              for (UnknownFieldData unknownField : unknownFieldData) {
                  unknownField.writeTo(output);
              }
          }
      }
  
      @Override
      public boolean equals(Object o) {
          if (o == this) {
              return true;
          }
          if (!(o instanceof FieldData)) {
              return false;
          }
  
          FieldData other = (FieldData) o;
          if (value != null && other.value != null) {
              // If both objects have deserialized values, compare those.
              // Since unknown fields are only compared if messages have generated equals methods
              // we know this will be a meaningful comparison (not identity) for all values.
              if (cachedExtension != other.cachedExtension) {  // Extension objects are singletons.
                  return false;
              }
              if (!cachedExtension.clazz.isArray()) {
                  // Can't test (!cachedExtension.repeated) due to 'bytes' -> 'byte[]'
                  return value.equals(other.value);
              }
              if (value instanceof byte[]) {
                  return Arrays.equals((byte[]) value, (byte[]) other.value);
              } else if (value instanceof int[]) {
                  return Arrays.equals((int[]) value, (int[]) other.value);
              } else if (value instanceof long[]) {
                  return Arrays.equals((long[]) value, (long[]) other.value);
              } else if (value instanceof float[]) {
                  return Arrays.equals((float[]) value, (float[]) other.value);
              } else if (value instanceof double[]) {
                  return Arrays.equals((double[]) value, (double[]) other.value);
              } else if (value instanceof boolean[]) {
                  return Arrays.equals((boolean[]) value, (boolean[]) other.value);
              } else {
                  return Arrays.deepEquals((Object[]) value, (Object[]) other.value);
              }
          }
          if (unknownFieldData != null && other.unknownFieldData != null) {
              // If both objects have byte arrays compare those directly.
              return unknownFieldData.equals(other.unknownFieldData);
          }
          try {
              // As a last resort, serialize and compare the resulting byte arrays.
              return Arrays.equals(toByteArray(), other.toByteArray());
          } catch (IOException e) {
              // Should not happen.
              throw new IllegalStateException(e);
          }
      }
  
      @Override
      public int hashCode() {
          int result = 17;
          try {
              // The only way to generate a consistent hash is to use the serialized form.
              result = 31 * result + Arrays.hashCode(toByteArray());
          } catch (IOException e) {
              // Should not happen.
              throw new IllegalStateException(e);
          }
          return result;
      }
  
      private byte[] toByteArray() throws IOException {
          byte[] result = new byte[computeSerializedSize()];
          CodedOutputByteBufferNano output = CodedOutputByteBufferNano.newInstance(result);
          writeTo(output);
          return result;
      }
  
      @Override
      public final FieldData clone() {
          FieldData clone = new FieldData();
          try {
              clone.cachedExtension = cachedExtension;
              if (unknownFieldData == null) {
                  clone.unknownFieldData = null;
              } else {
                  clone.unknownFieldData.addAll(unknownFieldData);
              }
  
              // Whether we need to deep clone value depends on its type. Primitive reference types
              // (e.g. Integer, Long etc.) are ok, since they're immutable. We need to clone arrays
              // and messages.
              if (value == null) {
                  // No cloning required.
              } else if (value instanceof MessageNano) {
                  clone.value = ((MessageNano) value).clone();
              } else if (value instanceof byte[]) {
                  clone.value = ((byte[]) value).clone();
              } else if (value instanceof byte[][]) {
                  byte[][] valueArray = (byte[][]) value;
                  byte[][] cloneArray = new byte[valueArray.length][];
                  clone.value = cloneArray;
                  for (int i = 0; i < valueArray.length; i++) {
                      cloneArray[i] = valueArray[i].clone();
                  }
              } else if (value instanceof boolean[]) {
                  clone.value = ((boolean[]) value).clone();
              } else if (value instanceof int[]) {
                  clone.value = ((int[]) value).clone();
              } else if (value instanceof long[]) {
                  clone.value = ((long[]) value).clone();
              } else if (value instanceof float[]) {
                  clone.value = ((float[]) value).clone();
              } else if (value instanceof double[]) {
                  clone.value = ((double[]) value).clone();
              } else if (value instanceof MessageNano[]) {
                  MessageNano[] valueArray = (MessageNano[]) value;
                  MessageNano[] cloneArray = new MessageNano[valueArray.length];
                  clone.value = cloneArray;
                  for (int i = 0; i < valueArray.length; i++) {
                      cloneArray[i] = valueArray[i].clone();
                  }
              }
              return clone;
          } catch (CloneNotSupportedException e) {
              throw new AssertionError(e);
          }
      }
  }
  